The importance of RNA sorting, targeted mRNA transport, and local protein synthesis has become evident as a result of the convergence of information from studies focusing on a variety of molecular, cellular and developmental questions. During the past fifteen years, over seventy intracellularly localized RNAs have been identified in a diversity of cell types in both vertebrates and invertebrates, ranging from oocytes to epithelial cells to neurons and glia. In addition, diverse classes of proteins are encoded by localized RNAs, including transcription factors, RNA- binding proteins, cytoskeletal proteins, proteases, intracellular signaling molecules and secreted growth factors. It is now clear that the targeting of mRNAs to particular intracellular locations plays a key role in biological processes that include the establishment of oocyte polarity, early embryonic differentiation, somatic cell polarization and function, synapse growth, and plasticity in the vertebrate nervous system. The goal of the proposed conference is to build on three highly successful FASEB summer conferences on the topic that were held in 1994, 1996 and 1998, buy bringing together researchers with a wide range of backgrounds and perspectives who study RNA sorting and localization using a variety of experimental approaches. It is the intent to explore common themes and questions including: (i) The role of RNA localization in the establishment of embryonic cell lineages and axial polarity in invertebrates and vertebrates; (ii) the nature of the cis-acting signals and trans- acting factors that target mRNAs to particular intracellular locations; (iii) the nature of the delivery systems that are involved; (iv) the mechanisms that anchor localized mRNAs once they reach their proper destinations; (v) definition of the nature and number of different destinations that reside within individual cell types; (vi) the extent to which mRNA translocation and sorting is regulated by extracellular and intracellular signaling processes; (vii) the mechanisms involved in transport of RNAs from the nucleus to the cytoplasm and in some cases from the cytoplasm to the nucleus; and (viii) the multiple ways in which RNA sorting plays a role in cellular function such as translational control.